Attachment site recognition and regulation of directionality by the serine integrases
Attachment site recognition and regulation of directionality by the serine integrases
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DOI：
10.1093/nar/gkt580
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发表时间：
2013-09-01
影响因子：
14.9
通讯作者：
Van Duyne, Gregory D.
中科院分区：
文献类型：
--
作者：
Rutherford, Karen;Yuan, Peng;Van Duyne, Gregory D.
丝氨酸整合酶通过噬菌体（attP）和宿主（attB）的“附着位点”之间的位点特异性重组，催化噬菌体DNA整合到宿主基因组中。反应是高度定向的；在没有噬菌体编码因子的情况下，产物attL和attR位点之间不会发生反向切除反应，其他配对的附着位点之间也不会发生重组。由于缺乏结构模型，对这些酶如何实现位点选择性和方向性的机制理解受到限制。在这里，我们报告了结合到atp DNA半位点的丝氨酸整合酶的c端结构域的结构。这种结构直接导致了理解整合酶结合的attP和attB位点如何不同的模型，为什么这些酶优先形成attP x attB突触复合物以启动重组，以及如何阻止attL x attR重组。在这些模型中，attP和attB半位点上的不同结构域组织允许整合酶亚基之间通过一个不寻常的突出的线圈基序形成附着位点特异性相互作用。这些相互作用被用来优先连接整合酶结合的attP和attB，并抑制整合酶结合的attL和attR的突触。研究结果为理解、测试和工程设计提供了一个结构框架。
Serine integrases catalyze the integration of bacteriophage DNA into a host genome by site-specific recombination between 'attachment sites' in the phage (attP) and the host (attB). The reaction is highly directional; the reverse excision reaction between the product attL and attR sites does not occur in the absence of a phage-encoded factor, nor does recombination occur between other pairings of attachment sites. A mechanistic understanding of how these enzymes achieve site-selectivity and directionality has been limited by a lack of structural models. Here, we report the structure of the C-terminal domains of a serine integrase bound to an attP DNA half-site. The structure leads directly to models for understanding how the integrase-bound attP and attB sites differ, why these enzymes preferentially form attP x attB synaptic complexes to initiate recombination, and how attL x attR recombination is prevented. In these models, different domain organizations on attP vs. attB half-sites allow attachment-site specific interactions to form between integrase subunits via an unusual protruding coiled-coil motif. These interactions are used to preferentially synapse integrase-bound attP and attB and inhibit synapsis of integrase-bound attL and attR. The results provide a structural framework for understanding, testing and engineering serine integrase function.